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RESEARCH PRODUCT

First and second viscosity measurements in superfluid 3He-B

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By means of diaphragm-driven flow experiments in 3He-B in a thin slab geometry, we have measured the first and second viscosities, η and 3 at pressures of 0, 5, 10 and 29.3 bar. Our measurement of 3 has better established theoretical foundations than previous measurements and also extends to higher pressures. 3 and η were deduced from the frequency dependence of the flow dissipation determined from bandwidth measurements for several normal modes of the diaphragm; a first order slip correction was used in the determination of η. Near Tc, 3 α (1 - T/Tc)-1/2 in accordance with theoretical predictions but below T/Tc ~ 0.6 we observe a rapid drop in 3 signifying a departure from the hydrodynamic limit.